Fix typo for proper config syntax

Change-Id: I34ffea1ec635e781f846312a3280fb609f131766
diff --git a/elasticsearch/files/elasticsearch.yml b/elasticsearch/files/elasticsearch.yml
index 5c4bc3e..2236031 100644
--- a/elasticsearch/files/elasticsearch.yml
+++ b/elasticsearch/files/elasticsearch.yml
@@ -159,7 +159,7 @@
 #
 # path.data: /path/to/data
 {%- if server.get('path', {}).data is defined %}
-path.data = {{ server.path.data }}
+path.data: {{ server.path.data }}
 {%- endif %}
 #
 # Can optionally include more than one location, causing data to be striped across